Note: Descriptions are shown in the official language in which they were submitted.
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DOWNSTACKE~ ~SSE~BLY
q'echnical ~ield
The present invention relates generally to the
field of material handling equipment, and more particu-
larly to an improved assembly for stacking paperboardproducts at high speeds.
Ba~groun~ Art
rrhe packaging of products in paperboard containers
or bo~es has increased so much over the years that a
very large packing industry has emeryed. It is conunon
to cut paperboard container blanks from planar sheets of
corrugated composition via rotating dies that operate at
very great linear speeds. The blanks are then removed
of excess trim and stacked flat in bundles for shipment
to points of usage.
The work function which is addressed by the present
invention is that of receiving, detrimming and stacking
paperboard flats or blanks from the aforementioned
rotary die cutters. The linear exit speeds o~ these
paperboard blanks can approach hundreds of feet per
minute, with up to one thousand feet per minute and more
being possible if the rotary die capability speeds are
matched. ~nfortunately, no prior art stackers have been
capable of reaching and maintaining such capability.
Interestingly, the stacking function has long been
addressed, such as by the continuous layboy taught by
Lamb in U.S. 2,205,767 (issued ~une 25, 1940), who even
then recognized that much had been accomplished in the
mechanization of stacking. In essence, Lamb presented a
main receiving table which was lowered at the rate of
stack build up, and a flnger table which was capable of
moving into position to temporarily catch the falling
blanks while unloading the main tableO
`~:
Ward and Wes-t, in a more recent and perhaps more
complete teaching in U~S. 4,500,243 (issued February 19,
19~5), taught a blank stacking apparatus utili~ing the
feature of receiving the paperboard blanks on-to an
inclined vacuum conveyor to deliver same to the lower
run of an overhead vacuum conveyor disposed over a
dropping chute. Release of the blanks is achieved by
timing the interruption of vacuum suction to the belts
(by the supporting pulleys~ just over t'he dropping area.
As the falling blanks settle upon an underlying con-
veyor, the conveyor is withdrawn downwardly as tne stack
builds. Side spanker assemblies tamp the stack to align
it. Once a stack is completed, a se-t of tines i5 exten-
ded to catch the blanks during unloading of the stack.
The disadvantage oE the Ward and Wes-t downs-tacker is t'he
difficulty in maintaining the timing sequence required
thereby at high operatiny speeds.
None of the prior art stackers known to the present
inventors achieves continuous, high speed stacking of
paperboard blanks and the like. It is to that end to
which the present invention is directed.
~iscl sure of the Invention
The present invention provides an improved down-
stacker assembly utilized for receiving and stacking
paperboard blanks from a die cutter assembly. Rows of
blanks are sequentially passed to a vacuum conveyor
assembly which holds and advances t'he blanks to a posi-
tion over a dropping chute. An impacting assembly
applies appropriately direc~ioned forces to the blanks
at t'he posi~ion over the drop chute to stop-the forward
advancement of t'he blanks and to separate the blanks
from the vacuum conveyor assembly so that the blanks are
caused to fall into the drop chute in a predetermined
angular disposition.
A stacking assembly which is disposed in the drop
chute beneath the vacuurn conveyor assembly receives the
falliny blanks -to form adjacently disposed stacks of
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blanks.
The impacting assembly is further characterized as
having plural rotatable cushion wheels as a striking
surface ayainst wl1ich the advancing bla.nks irnpact, and a
blank striker assembly which knocks the rear por-tion of
the blanks away from the vacuum conveyor assembly just
prior to impact of the leading edges of the blanks
against the striking surface~
'rhe stacking assembly is characterized as having a
platform assembly disposed at least partially in a pit
beneath the falling blanks, and a tamper assembly which
tamps the side edges of the blanks as the stacks are
forming to provide substantially uniform sides to the
stacks. Flexible curtains a.re provided to hang between
adjacent stacks be.ing formed on the platforril assemb:Ly in
order to provide a flexible back up between adjacently
disposed stacks so that substantially no gap exists
between adjacent stacks.
A stack retrieval assembly is provided for
receiving the blank stacks from the platform assembly
after the platform assembly is lowered in the pit and
for eleva-ting the blank stacks to at least floor level
elevation upon discharge of same.
The stacking assembly also comprises a stack
staging assembly which is selectively disposable beneath
the vacuum conveyor assembly to-temporarily collect
falling blanks during unloading of-the already collected
stacks from the platform assembly. Interrupt control o~
blank Eeeding can be ernployed to momentarily interrupt
the passing of the blanks to the down stacker assembly
to provide a gap in the passage of the blanks to the
vacuum conveyor assembly during -the interval when the
stack staging assembly is being moved into position
beneath the vacuum conveyor assembly.
A trim removal conveyor is utilized for receiving
the blanks from a die cutter assembly, the trim removal
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conveyor coinprising a sandwich conveyor assembly which
has a lower rope conveyor and an upper web conveyor, and
a beater assembly disposed to vibrate the upper web
conveyor against the passing blanks to beat the trim
free and to cause same to fall between the ropes of the
lower rope conveyor.
Further, a feed station assembly haviny a plurality
of endless conveyor belts perforated to vacuum hold and
spread the blanks is utilized to move the blanks from
the trim rernoval station to the vacuurrl conveyor
assembly.
The primary object of -the present invention is to
provide a downstacker assembly capable of achieving high
speed downstacking of paperboard blanks from a die
cu-tter assembly.
Another objec-t of the present invention is to
provide such a downstacker assembly which achieves the
above stated object at a minimum capital investment cos-t
and minimum maintenance requirements, and which can be
operated with a minimum o-f operator attention.
Other objects, advantages and features of the
present invention will become clear from the followiny
description of the preferred embodiment when read in
conjunction with the accompanying drawings and appended
claims.
Brief Des~riptio~ of the Dr~wings
_
Figure 1 is a perspective view of a downstacker
assembly constructed in accordance with the present
invention. For clarity, portions of the downstacker
assembly are removed to disclose certain details
thereof. Figure lA is a profile schematic depicting
relative locations of the major components of -the
downstacker assembly.
~igure 2 is a side elevational view of the down-
stacker assembly of Figure l. For clarity, the down-
stacker assernbly is depicted in ser[~i-de-tailed view in
Fiyure 2.
Figure 3 is a semi-detailed, partial cutaway, side
elevational view of portions of the trim removal
station. Figure 3A is a plan view of the upper web
conveyor with the belts rernoved therefrom. Figure 3B is
a plan view, in partial cutaway depiction, of the lower
rope conveyor.
E'igure 4 is a top plan view of the feed s-tation.
Li'igure 5 is taken at S - 5 in Fiyure 4.
Figure 6 i8 a top plan view of the vacuum conveyor
station.
Figure 7 is a semi-detailed, semi-schematic view in
side elevation of the vacuum conveyor sta-tion.
E'igure 8 is a view taken at 8 - 8 in Figure 6.
Figure 9 is a view taken at 9 - 9 in Figure 8.
Figure lO is a partially detailed depiction of the
side rail support of the lateral support beam oE the
vacuum conveyor station.
Figure ll is a schematic representation depicting
-the relative positions of the stationary backstop and
the movable bac~stop of the downstacker station.
Figures 12 and 12A are front eleva-tional and top
plan views, respectively, of the stationary backstop.
Figure 12B is a side elevational, schematic representa-
tion of a portion of the stack staging assembly suppor-
ted by the stationary backstop. Figure 12C is a partial
cutaway view of the fork extension mechanism. E'igure
12D is a par-tial detailed, side elevational view of a
portion of the tarnper assernbly supported by the
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stationary backstop.
Figure 13 is a side elevational, semi-detailed view
of the movable backstop.
Figure 14 is an enlarged view of a portion of the
movable backstop shown in E'igure 13.
Figure 15 is a side elevational, semi~detailed view
of one of the side tamper plates.
Figure 16 is a side elevational view of a flexible
curtain mechanism.
E'igure 17 is an enlarged detail of the dunnaye
clamp assembly disposed a-t the discharge opening oE t'he
downstacker station.
Figure 18 is a schematic diagram of the control
systern for the downstacker assembly.
~est Mode ~or Carr~in Out the Invention
Like numerals and characters designate like
elemen-~s throughout the figures of the drawings.
Reference is initially directea to Figure 1 which
shows in perspective view a downstacker assembly con-
structed in accordance with the present invention.
E'igure lA is an outline of the major stations that
comprise the downstacker assembly, and this outline is
provided for convenience in locating the positions of
the stations. More specifically:
10 depicts the downstacker assembly.
12 is a trim removal station, and as shown, has its
sandwich conveyor assembly partially open for mainten-
ance access.
14 is a feed station.
16 is a downstacker station.
18 i5 a vacuum conveyor assembly portion of the
down stacker station 16. As shown, the vacuum conveyor
1~ is partially opened as when maintenance access is
afforded.
20 in Figure 2 is a concrete floor upon which the
downstacker assembly lO is supported. As used herein,
floor level elevation means the elevation of the con-
crete floor ~0.
22 is a pit into which a portion of ~he downs-tacker
station 16 is disposed.
24 d~picts the profile of a rotary die cutter
assembly which cuts paperboard blanks from a web or
sheets of cardboard and the like.
Figure 2 is a side elevational depiction of these
assemblies showing -their positional relationship to the
die cutter assembly 24 which directs cut blanks with
trim to the trim removal station 12. The trim removal
station 12 knocks the trim from the blanks and moves the
blanks onto the upper surface of the feed station 14.
The feed station 14 is an inclined vacuum conveyor which
does two functions: it separates the laterally adjacent
blanks and an inch or so apart as the blanks are moved
up an incline to the lower run of the vacuum conveyor
18.
The vacuum conveyor 18, as will be made clearer,
moves the blanks to a position over a drop chute, and
other mechanisms forcibly remove the blanks from the
vacuum conve~or so that the blanks fall onto -the pro-
gressively lowering platform conveyor disposed withinthe pit in the drop chute area. E'or the discussion
which follows, the paperboard blanks are substantially
flat cardboard members having forward and rear portions
with leading edges and rear edges, respectively.
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Figures 3, 3A and 3B snow vario~ls partial views of
the trim removal station 12. Many details of the trim
removal station 12 are conventional and will be omitted
in the interest of brevity.
26 is a lower suppor-t frame and is also viewable ln
part in Figure 1.
2~ is a sandwich conveyor assembly supported by the
support frame 26 and is comprised of the following:
30 is a lower rope conveyor assembly;
32 is an upper web conveyor assembly portion of the
sandwich conveyor assembly 2~. The ~eb conveyor assem-
bly 32 has an upper box frame 32A which is pivo-tably
connected to the lower support frame 26 for pivoting of
the web conveyor assembly 32 to an open position by
pivoting support rams (viewable in part in ~igure 1).
34 is a pair of flexible endless web belts disposed
over spaced apart arbors 34A and 34B (~igure 3A shows
the upper web conveyor assembly with the web belts 34
removed in order to show details of s-tructure). A drive
arbor 34A is powered by a sheave and belt ~not shown)
attached outboard to this arbor. A pair oE arbors 34B
are coaxially mounted so as to be adjustable to accommo-
date and matted conventionally to adjust to the stret.ch
length of the belts. Also, an adjustable mid arbor 34C
is provided.
36 and 38 are a pair of beater mernbers that are
disposed in parallel relationship to the arbors 34A, 34B
and 34C and supported by the same cross :Erame members.
Each of the beater members is comprised of the follow-
ing.
40 is a central drive shaft driven by a sheave andpower belt (not shown~ attached outboard thereto;
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4~ depicts a plurality of sæaced apart spacer mem-
bers supported alony each of the beater members 36, 3~3.
44 depicts a plurality of'beater bars bridging and
supported by various ones of the spacer members 42.
46 and 4~ are grooved arbors supported in spaced
apart disposition via the frame 26, as shown in Figure
3B.
50 is a power drive assembly for the grooved arbor
48.
52 depicts a plurality of flexible, endless rope
members that are disposed over the grooved arbors ~6,
ive suc'h rope members 52 are shown in I~ligure 3B
for illus-tration, but t'he nurnber of such belts is vari-
able and other such belts can be run in the remaining
grooves shown on the arbors 46, 48. In general, the
number and spacing of such rope menibers 52 will depend
upon the package and trim profile fed from the rotary
die cutter assembly 24, with the rope members 52 being
disposed to support the blanks while being sufficiently
spaced to permit trim droppings therebetween.
54 are adjustment arbors disposed beneath the top
run of the rope members 52, each of which has a cam lift
device 54A which elevates or lowers the adjustment arbor
54 upon turniny of a se-t handle 54B.
The endless belts 3~ are preferably made of rein-
forced rubber or flexible plastic material havin~ knob
like protrusions in a pattern that generally makes
multiple po:int contact against the top of the paperboard
blanks and trim received from t'.he cutter assembly 2~.
Figure 3 depicts tlle lower rope conveyor assembly 30 and
the upper web conveyor assembly 32 in parallel, spaced
apart disposition; this is for illustration only. In
actuality, the upper web conveyor assembly 32 is pivot-
ally attached at one end to the suppor-t frame 2~ and i5
pivotable to the open position shown in ~igure 1 via
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appropriately disposed hydraulic rams. In the closed
position, the lower runs of-the web belts 34 are brouyht
lnto close position to the upper runs of the rope mem-
bers 5~. In operation, the driven ro-tation of the
central drive shafts 40 causes the bea~er members 36, 38
to beat against the web belts 34 as the beater bars 36,
38 rotate and strike the belts. This cre~tes continuous
vibratory motion in the web belts 34 which is imparted
to the paperboard blanks, causing the trim portions to
be separated from the blanks and to be directed down-
wardly between the rope members 52. The intensity of
this vibratory motion on the paperboard blanks can be
adjusted by the adjustment arbor 54 of the lower rope
conveyor 30. Of course, the number and spacing of the
rope members S2 on -the grooved arbors 46, 48 are estab-
lished to support -t'he blanks while permitting trim
removal to fall therebetween, with an appropriately
positioned chute disposed -therebeneat'h to eject collec-
ted trim to a disposition conveyor (not shown). I'he
paperboard blanks less trim are directed via the trim
removal station 12 to the feed station 14.
The feed station 14 is a spacing conveyor which
moves the paperboard blanks received from the ~rim
removal station 12 to the downstacker station 16. For
operational convenience, the pit 22 is provided in order
to lower the height of the downstacker station 16 for
improved operator and maintenance accessibility. Also,
the feed station 14 is inclined to accommodate the
difference in elevation between the die cutter assembly
24 and the vacuum conveyor station 1~ of the downstacker
station 16, and the pit 22 minimizes this incline. The
feed station 14, as shown in Figure 2, spans the dis-
tance between the die cutter assembly 24 and the trim
removal station 12, and comprises-the following details
of construction~
58 is a supporting framework.
60 is a conveyor assembly supported by the support-
ing framework 58. As shown, one or more'hydraulic rams
58A can be provided to l.ift or tilt the conveyor assem-
bly 60 upwardly or underside accessibility.
61 is a conveyor box frame whic'n appears in Eigure
4.
62A throuc3h 62J are a plurality of con~eyor belts.
64 depicts a plurality of sheaves supported at the
lower end of the conveyor box frame 61 on a common drive
shaft 64A which is supported by appropriately disposed
journalled bearings along the end of the box frame 61.
6~B depicts a drive belt assembly for rotating the
sheaves 64 and thus the conveyor belts 62A - 62J
together in the direction indicated by -the flow arrow.
66A th.rough 66J depicts a plurality of individually
journalled sheaves at the upper end of the box frame 61,
each such sheave supporting its individual conveyor belt
62.
68A through 68J depicts a plurality of vacuum cham-
bers supported beneath the upper runs of the conveyor
belt 6~A through 62J, as shown.
69 depicts the hollow core of the vacuum chamber
68A which is shown in cross sectional view in F'igure 5
(taken at 5 - 5 in Figure 4). A belt support member 68D
is attached to the upper end of the vaccum chamber 68A
and has upwardly extending edges to confine the belt 62A
in its continuous travel along the length of the vacuum
chamber 68A. ~he belt support member 68D can be made of
a wear resistent, polymeric material, if desired. A
slot 68E is provided in the upper end of the vacuum
chamber 68A and in the box support member 68D. A series
of spaced apart apertures 68F are provided in the con-
veyor belt 62A which communicate via the slot 68E with
the core 69 of the vacuum chamber 68A.
A conventional vacuum system is provided, part of
which is shown beneath the feed station 14 in ~igure l,
~v~
to produce a vacuum in the core 69 and consequen~ly at
the apertures 68~'in-the conveyor belt 62A. It will be
unders-tood that the description for the conveyor belt
62A and its supporting structure also applies to the
construction details of the remaining conveyor belts 62B
through 62J' and the supporting vacuum chambers 6~
through 68J thereof. Thus, with applied vacuum, all of
the conveyor belts 62A - 62J present an array of travel-
ing vacuum apertures 68F. As paperboard blanks are
received onto the upper runs o~ t'ne conveyor belts 62A
through 62J, the blanks are moved up the incline of the
conveyor assembly 60 and are fed to -the vacuum conveyor
station 18 as described further below.
It will be remembered frorn the description above
-that the sheaves 64 are commonly supported via the drive
shaft 6~, while each of the sheaves 66A through 6~J is
individually supported on the opposing end of the box
frarne 61. I'he purpose of the latter arranyement is to
permit some lateral adjustment to the conveyor belts 62A
through 62J at the upper end of the box frame 61. That
is, each of the sheaves 66A through 66J is supported
(such as illustrated for sheaves 66A in Figure 4) via
bolts 66K throuy'h slotted flanges which support the
sheaves 66A for ro-tation. This permits some lateral
adjustment to each of the sheaves 66A through 66J in a
lateral direction so that the spacing between the con-
veyor belts 62A - 62J at the upper end of the box frame
61 can be selectively set to be greater a-t this end than
at the lower end of the box frame 61. In other words,
the conveyor belts 62A through 62J can be caused to
diverge slightly in the direction of flow. Of course,
the slack in the conveyor belts must be variable, so a
conventional belt tension regulator (not shown) is pro
vided which gives some slack during adjustment and then
permits belt tightening. Also, the upper ends of the
underlying vacuum chambers 68A ~ 68J must be allowed
lateral adjustment to track such lateral adjustment of
the sheaves 66A - 66J, such as by a slideable lip sup-
port (not shown).
~u~
The above described lateral adjustment is provided
so that the paperboard blanks can be caused to separate
slightly as such blanks are moved -toward the upper end
of the conveyor assembly 60. This small lateral separa-
tion given to the adjacent blanks is provided to preventinterference between adjacent blanks as these blanks are
caused to fall into s-tacks in -the downstacker assembly
15.
The vacuum conveyor station 18 is comprised of a
plurality of parallel conveyor belts which serve to move
the paperboard blanks from the feed station 14 to over a
drop chute in the downstacker station 16. As shown in
Figure 6, the vacuum conveyor station 18 comprises the
following structural details.
70 is a box frame whic'h is pivotally supported at
one end by a vertical frame o~ the downstacker s-tation
16 described below, and ra~ls 70A (one of which is s'hown
in Figure 1) are provided to raise the vacuum conveyor
sta-tion 18 to the position shown in Figure 1.
72 depicts a plurality of conveyor belts, with the
individual belts being enumerated 72A through 72J.
74 and 76 depict plural sheaves supporting each of
the conveyor belts 72, with 74A through 74J depicting
the sheaves at one end and 76 depicting the sheaves at
the other end of t'he frame 70. The sheaves 74A through
74J are individually supported with each being supported
for slack adjustment of its respective conveyor belt.
78 depicts a common support shaft for all of the
sheaves 76, the support shaft 7~ being bearingly suppor-
ted on the frame 70.
80 is a drive assembly for rotating the sheaves 78and consequently the sheaves 76 in unison to drive the
conveyor belts 72A through 72J to move in the direction
indicated by the flow arrow.
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82 depicts a plurality of vacuum chambers supported
by the frame 70 beneath each of the conveyor belts 72A
tnrough 72J. One of -the vacuum chambers is viewable in
the semi-detailed view of E'igure 7. Each of the vacuum
chambers is construc-ted similarly to the vacuum chambers
68 of the conveyor assembly ~0, and the conveyor belts
72A - 72J, which have a plurali~y of apertures similar
to the above described conveyor belts 62, are caused to
have vacuum suction in the same manner as the inclined
conveyor of Fiyure 4, with the exception that the vacuum
chambers 82 are inverted so that the vacuum is provided
along the bo-ttom runs of the conveyor belts 72A - 72J
for the purpose discussed further below. q'he vacuum
system used to create reduced pressure :in the vacuum
chambers 8~ is converltiollal and need not be described.
84 is a blank impacting assembly which absorbs the
momentum of the horizontally moving blanks and which
separates the blanks Erom beneath the conveyor belts 72A
through 72J. A portion o~ the blank impacting assembly
84 is depicted by 84A which is a blank striker assembly
and which comprises the ollowing construction details.
86 is a pair of rails supported along each side of
the frame 70.
88 is a lateral support beam slidingly supported by
the rails 86 and locked thereto in the manner described
below.
90 is a droppiny chute in the downstacker station
16 disposed beneath the conveyor belts 72A - 72J. In a
manner to be made more clear below, the purpose of the
blank striker assembly 84A is to apply striking forces
to the blanks carried beneath the conveyor belts 72A -
72J above the dropping chute 90 to separate the blanks
from the vacuum conveyor station 18. Also, to be
described hereinbelow, the blank impacting assembly 84
comprises a plurality of wheels which are disposed so as
to be impacted by the forward edges of the paperboard
blanks to cease the forward advancement of the blanks so
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that the blanks separated from the underside of the
conveyor belts 72A - 72J, are caused to fall in the drop
chute in a predetermined angular disposition and to
stack uniformly in -the downs-tacker station 16.
92 depicts a plurality of strikers supported at
intervals along the lateral support beam 88, one of the
strikers 92 being shown in proiile in Figure 8, a
descrip-tion of which will be co~lmon for all of such
strikers g2. The striker 92, as shown in Figures 8 and
9, comprises t'he following structural details.
94 is a support frame and brace attached to the
underside of the lateral support bea~ 88.
96 is a striker device supported at t'he lower end
of the frame 9~ and comprises a spring clutch mechanisrn.
98 depicts the clutch body portion of the striker
device g6 whic'h isllloun-ted for ro-tation on the frame 9
and which has a locking year 98A extensive t'herefrom.
~ot shown in the partial cutaway view of Figure 9 is a
spring mounted latch and solenoid mechanism which selec-
tively engages the locking gear 98A.
100 is a rotatable striker arm connected to the
clutcn body portion 98. The clutch body portion 98 is a
spring clutch oE the type manufactured by Warner Elec-
tric Brake and Clutch Company of South Beloit, Illinois,
~5 and is pre~erably Model ~'umber 275-1-0006, C~-2 series.
At one end of the clutch body portion 98 is a pulley
portion 98B for rotating the striker device 96. As the
pulley portion 98B is caused to rotate, the latch
- engages the locking gear 98A which sets the striker arm
100 at a predetermined rest position. ~'he pulley por-
tion 98B, however, ls always free to ro-tate. When the
solenoid (not s'hown) is energized, the latch is lifted
and the striker arm 100 can rotate with the pulle~
portion g8B. The striker arm lO0 is spatially disposed
beneath the lateral support beam 88 between a pair o:E
adjacent conveyor belts 72 so as to be in position-to
~L3~3~
strike a paperboard blank carried at the underside of
the conveyor bel-ts 72.
102 is a drive shaft bearingly supported via
several bearing supports 102A alon~3 one side of the
lateral support beam 8~ and having a plurality of pul
leys 102B, one each of such pulleys 102B being provided
for each striker g2. A pulley belt 102C is driven by
each of the pulleys 102B and drivingly en~ages the
pulley 102~ of each striker 92.
104 is a power assembly provided to rotate the
drive shaft 102 and thus to drive all of the pulleys 98B
of the strikers 92 together. This provides for the
s-triker arms 100 to reac-t in unison as the solenoids of
the clutches 98 are energized together, thereby provid-
ing multiple strik:ing blows against the paperboard
blanks across the underside of the vacuum conveyor sta-
tion 1~.
As depicted in Figure 10, each end of the lateral
support beam 8a is suppor-ted by one of the rails 86, and
a lockiny member ~A is provided so as to secure same
thereto at a selec-ted location along the rails 86. The
purpose of this is to enable the positioning of the
blank striker assembly 84A such that the strikers 92 are
disposed just over the rear portions of the paperboard
blanks regardless of the size of the blanks (that is,
within the confines of the machine dimensions). This
results in the strikers 92, driven in unison, being
caused to strike the blanks a-t a predetermined position,
and in a timed manner as described more fully below, to
knock the rear portions of the blanks down and away froln
the underside of the vacuum conveyor belts 72.
Returning to E'igure 1, depicted as supported within
the pit 22 is the downstacker station 16. More speci-
fically, -the downstacker station 16 is comprised of the
following construction details.
110 is a vertically extendinc~ box frame which is
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partially disposed within the pit 22 and which has a
stacking compartment and an unstacking compartLnent
designated by the following numerals.
11~ ls the stacking compartment which is open on
the side shown and which has a slideable safety door
112~ guarding access to the drop chute gO.
114 is the unstacking compartment which is open as
shown and which has a slideable safety door 114A guard-
ing access to entry thereof.
11~ is a stacki.ng assembly portion of the down-
stacker station 16 and is disposed in the drop chute 90
beneath the vacuum conveyor station 18 Eor receiving the
falling blanks and for forming adjacently disposed
stacks o:E pQperboard blanks.
118 is a first elevator or conveyor por-tion of the
stacking assembly 116, and which is disposed within the
stacking compartment 112. The first elevator 118, also
sornetimes herein reEerred to as a platform assembly, has
a set of conventionally powered rollers 118A that are
driven by a power source to rotate counter-clockwise (in
Figure 2) to move paperboard b~anks in the direction of
the flow arrow. ~ot shown is a chain and sprocket
arrangement, conventional in nature with counterweights,
for selectively lifting and lowering the first elevator
118 within the stacking compartment 112. The rollers
118A serve as a pla-tform surface for receiving blanks
falling in the drop chute into stacks; as the stacks
form, the first elevator 11.8 is progressively lowered by
conventional power and control circuitry until a selec-
ted stack height is formed.
120 is a stack re-trieval assembly disposed within
the unstacking compartment 114 and comprises a second
elevator or conveyor 120A w~ich, in similar manner to
that of the first elevator 118, is supported by a con-
ventional chain and sprocket arrangement (not snown)which is capable of selec-tively raising and lowering the
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second elevator 120A. In its lowered position, the
second elevator 120A is aligned with the first elevator
118 (in lts lowered position) to receive stacks of
paperboard blanks therefrom. The second elevator 120A
also has a set of conventionally powered rollers.
122 is a stack pusher assembly (viewable in Fiyure
1) which is disposed to move the stacks received on the
second elevator 120A in the direction of the flow arrow.
The stack pusher assembly 122 has an arm which is posi-
tionable across the second elevator 120A once the stacksare received thereon, the arm being supported on each
side of the second elevator 120A via traveler members
which are driven via powered chain drives. The stack
pusher assembly 122 is necessary to move stacks.
124 depicts a receiving conveyor disposed at an
outlet opening of the unstacking compartmerlt 114. In
discharging the stacks of collected blanks from the
stack retrieval assembly 120, the second elevator 120A
is elevated to align with the receiving conveyor 124, at
which time the stack pusher assembly 122 is activated to
push the stacks onto the receiving conveyor 124 for
removal via conventional means (not shown~.
126 is a dunnaye clamp assembly which is supported
by the frame 110 at the end of the receiving conveyor
124. This dunnage clamp 126, shown in partial detail in
Figure 17, has a stationary frame member 126A which has
an upstanding first gripping member 126~ extending the
width of the receiving conveyor 124.
128 is a second gripping member pivotally attached
at its lower edye to the stationary frame member 126A.
130 is a conventional pancake type cylinder having
an extendible rnember attached to the second gripping
member 128 Eor selectively pivoting the second gripping
member 128 to the open position depicted in ~iyure 17
and to a closed position in which the second gripping
member 128 is pivoted to bear against tlle first gripping
~3~
--1 9 -
rnember 126~.
The purpose of the dunnage clamp assembly 126 is to
permit the placement and retention of dunnage under the
stacks pushed from the second elevator 120A onto the
receiviny conveyor 124, the dunnage being necessary for
the bindin~ straps placed about the stacks during the
colligation process. Prior to receiving the stacks on
the receiving conveyor 124, one edye of a piece of dun-
nage, typically a flexible sheet of cardboard or the
like, is placed between the first gripping member 126
and the second gripping member 128 (in the open posi--
tion), and the cylinder 130 is actuated to close the
second gripping member 128 to securely grip the dunnaye.
The dunnage is t'hen folded downwardly so as to overlay
t'he end of the receivilly conveyor 124. Once the stacks
of 'blanks are pushed onto the dunnage, the cylinder :L30
is actuated to open t'he second gripping member 128 to
release the dunnage and to permit the stacks and dunnage
to be moved along the receiving conveyor 124.
2~ Continuing now with other portions of the down-
stacker assembly 16t and more specifically with the
blank impacting assembly 84, disposed within the stack-
ing compartmen-t 112 is a stationary backstop and a
movable backstop, the details o:E which will now be
discussed.
132 and 134 depict, respec-tively, the stationary
backstop and the movable backs-top, as viewable in the
semi-detailed, partial schematic of Figure 11. This
figure is provided to give a general layout of these two
backstops, the construction details of which will fol-
low. Discussion will first be given with reference to
Figures 12 and 12A which are views of the stationary
backstop 132.
136 is a laterally extending frame supported by the
box frame 110.
138 is a support arbor which extends across, and is
~3~
--~o--
bearingly supported on, the frame 13~. A power train
(not shown) connected outboard to the support arbor 13
for bidirectional rotation thereof.
140 depicts a plurality of cushion wheels supported
along the arbor 138 and which are disposed to be in the
hori~ontal path of the paperboard blanks carried by the
lower run of the vacuum conveyor assembly 18. That is,
cus`nlon wheels 140, having a semi-flexible striking
surfaces~ are disposed in the advancing pa~h of the
blanks so as to be struck by the leading edges of the
blanks when the blanks are advanced over the drop chute
90. The rear portions of the blanks having just been
struck downward blows by the strikers 92, the cushion
wheels 140 impart a stopping force to the leading edges
of the blanks, thusly effecting an angular disposition
to the falling blanks, preferably with the rear edges of
the blanks falling before the leading edges thereo~.
The arbor 138 supports and rotates the cushion wheels
140 in unison at a relatively low rotational speed just
suficient to present fresh impact surfaces regularly to
the impacting blanks. The direction of rotation of the
cushion wheel 140 is selected such that, upon impact by
the blanks, the blanks will be caused to rebound with a
proper force component. That is, it may be necessary to
set -the rotational direction differently, to modify the
speed, or even stop the rotation for any particular
paperboard blank as the characteristics of such blanks
can vary greatly. In general, a downward vector a-t the
leading edges of the blanks will be desired, as this
assists in the dropping motion o~ the blanks. ~owever,
experience seems to indicate that other blank character-
istics, such as pliancy of the leading edges, will also
bear upon the rotational direc~ion selection.
q'he movable backstop 134 has a good many similari-
ties to that discussed above for the stationary backstop
132, and more details of same will be provided herein-
below. ~eanwhile, with further discussion of the
stationary backs-top 132, it will be noted that this unit
also serves to support portions of the stacking assembly
~3gJ`2~7
-21-
116; more specifically, the stationary backstop 132
supports part of a tamper assembly which serves to
tamper the edges of -the blanks as stacks of paperboard
blanks are formed to provide substantially uniform sides
to such stacks, and details of such tamper assembly are
to be found in Figures 1~ through 16.
142 is a tamper plate bearingly supported by the
arbor 138 via hanging tabs 14~A as shown in Figure 12D.
144 depicts a powered cam mechanism which has
several rotatable cams 144A that are connected to the
tamper plate 142 via spring linkages as s'hown. Rotation
of the cams 144A causes the tamper plate 142 to oscil-
late, and the disposition of-the-tamper plate 142 in
front of the cus'h:ion wheels 140 causes the tamper plate
142 to tamper the leading ed~es of the blanks as such
form stac'ks in the drop c'hute gO.
146 is a tamper plate shown in Figure 15 in partial
detail. The tamper plate 146 is pivotably supported hy
a cantilever frame 146A which is slideably supported on
a rail member 146B which, although not shown in Figure
12 and 12A, is mounted to the frame 136 and extends
therealong above the cushion wheels 1~0. The frame 146A
can be attached to a laterally extending screw membe.r to
move it to a position such that the tamper plate 146 is
disposed adjacent to the outside edges of one of the
outermost stacks formed on the first elevator 11~. An
oscillator cylinder 146C, upon activation via a power
source (not shown), oscillates the lower end of the
tamper plate 146 to tamp the outside edges of the stacks
being formed in the drop chute 90. Another tamper
plate, identical in construction to the tamper plate
146, is provided on the opposite side stacks to tamp the
opposing edges of the stacks. ~he la-terally extendin~
screw member, provided with two sections of oppositely
pitched threads, can be rotated to move the tamper
plates toward or away from each other to define the
width of the dropping chute 90.
13~ 7
-2~-
Because -the paperboard blanks are separated via the
above discussed divergence lmparted by the conveyor
assembly 60 of the feed station 14, the stacks will tend
to form with gaps between adjacent stacks on the first
elevator 118. While these yaps serve the useful feature
of preventing side in-terference between falling blanks
in the drop chute 90, it is desirable that the stacks be
brought -together once ~ormed, as such gaps remaining
between stacks, when banded on the receiving conveyor
124, will result in a certain amount of difficulty as
the bundled stacks are transported~ To prevent this ill
effect, the present invention provides flexible cur-tains
extending be-tween adjacen-tly disposed stacks to permit
sufficient edge tampering to bring adiacent stacks into
near touching, bu-t not overlapping, disposition. One
such curtain mechanism is shown in E'igure 16, where the
following numeral desigations are found.
148 is a flexible curtain mechanism which has a
clampiny support frame 148A.
150 depicts a slide rail frame variously extendible
from the support frame 148~ and which is set at a
desired extension via set screws 148A iIl support loops
148C. As shown, the support frame 148A can be position-
able along a lateral rail portion of the box frame 110
at a desired position, or if desired, the support frame
of the curtain mechanism 148 can be configured to be
supported by the rail member 146B (mentioned above for
the tamper plates 146) and can cantilever out therefrom
to permit proper placement.
152 is a flexible curtain member supported by the
slide rail 150 to hang between adjacent s-tacks beiny
formed on the platform surface of the first elevator 118
to provide a flexible backup between stacks of blanks
while being tamped by the tamper plate 142 and tamper
plates 14~ so that adjacently forming stacks are made to
be in near touching engagement wit.h substantially no gap
therebetween. As the first elevator 11~ is lowered
during stack formation, the stationary curtain ~52 is
~23-
caused to be withdrawn from be-tween -the stacks. The
number of such curtains 1~?, and the size thereof, will
be determined by the number of stacks and the size of
t'he paperboard blanks.
The stacking assembly 116 also includes a stack
staging assembly which is positionable beneath the
vacuum conveyor station 18 for collecting falling blanks
after a selected stack height has been achieved on the
firs~ elevator 118. That is, it is desirable that the
flow of paperboard blanks be continuous and not inter-
rupted during the time necessary to transfer the stacks
from the first elevator 118 to the second elevator 120A.
To -this end, the following construction de-tails of ~he
stack staging assembly are provided, s-tartiny first with
reference to Figures 12 and 12A.
154 is a portion oE t'he stack staging assembly, of
whic'h 154A is a first fork set. The firs-t fork set 15~A
comprises the following construction details.
156 is a lateral beam member from which a plurality
of fork members or tines 156A extend. A side profile is
viewable in Figure 12~. 'rhe fork members 156A are
slideably supported via a bearing block 156B supported
at the ends thereof via guide posts (not shown) and via
a plurali-ty of screw members 156C which are in turn
supported by the frame 136. As shown, the forks are
extensive through slots in -the fron-t of the frame 136.
'Lnternal to the block 156B are appropriately disposed
bearings ~not shown) to slidingly suppor-t the fork mem-
bers 156A; also internal to the block 156B are gear
members which interact wi-th the screw members 156C such
that, upon rotation o~' t'he screw members 156C via con-
ventional in-terconnec-ted bear boxes 156D and power train
156E, the forks 156A, and consequently the lateral beam
member 156, can be raised and lowered relative to the
~rame 136 as the block 156B is moved along the s~rew
member 156C, via -the power train 156E. The dashed lines
in Figur~ 12B indicate the forks 156A in a lowered and
extended position. Extension and retrac-tion of the
:~L3~)Z~
-24-
forks 156A is accomplished as follows.
158 depic-ts a pair o~ rack gear members supported
by the la~eral beam member 156 and extensive parallel -to
the forks 156A. The par-tial cutaway view o~ Fiyure 12C
S shows a portion of one of these rack gear members in
greater detail.
160 is one of a pair of a rotatable arbors beari.ng-
ly supported by the bearing block 156B, and as shown in
Figure 12C, each of the arbors 160 has a lower gear 160A
is disposed to interact with one of the rack gears 158
extensive throuyh the bearing block 156B. 160B depicts
a top gear which is supported by each arbor 160 and
which ls disposed to interact with a rack gear 160C.
The rack gear 160C will be more clearly viewable with
lS reference to ~igure l~A once aga:L~, where the rack gear
160C is partially viewable in a cutaway detail.
162 is a double actiny cylinder which is supported
by the bearing block 156B with a first end thereof,
depicted as lG2A, attached to a tab member 162B ex-ten-
sive from the bearing block 156B, and a second end 162Cof the cylinder 162 connected to the rack gear 160C via
a tab member 162D extensive therefrorn. With selective
actuation of the cylinder 162 fluid power control (not
shown), the rack geax 160C is caused to slide la-terally
relative to the bearing block 156B.
Returning to Figure 12C, it will be seen that-the
rack gear 160C is slideably retained on the bearing
block 156B via a suppGrt member 156D in conventional
manner. Again, as the cylinder 162 is actuated, the
rack gear 160C is moved thereby, interacting with the
gears 160B to rotate the arbors 160. This causes the
rotation of the gears 160A, which causes the rack gears
1S8 to move relative to the bearing block 156B. Since
-the rack gears 152 are attached to the lateral beam
member 156, this causes the beam 156 to move toward or
away from the bearing block 156B, thereby causing the
forks 156A to move between the retracted and extended
~3~ 7
-25-
positions relative to the frame 136. More about this in
the discussion of the second fork set supported in
simiLar fashion on the movable backstop 134 will clarify
the function of these fork sets.
Turning to Figure 13, therein is depicted a side
elevational view of the movable backstop 134 in which
the components -thereof are enumera~ed as follows.
164 is a laterally extending frame slidingly sup-
ported at each end via a pair of support rails (not
s'hown) which are in turn supportsd by the box frame 110.
Also, a pair o screw rails 164A are provided to selec-
tively move and position the frame 1.64. The rails 164A
also appear in Figures 12 and 12A w'here a drive traln
16~B is shown for the simultaneous rotation o:E t'he rails
164A to rnove t'he movable bac]cstop 13~ to a desired
position along the rails 164~ via interaction therewith
by appropriately disposed gears (not shown) in the frame
164.
166 depicts a portion of a power train which drives
a laterally disposed arbor (not shown) to efect the
raising and lowering of the second fork set 154B. The
structural details of the second fork set 154B are iden-
tical to that provided above for the first fork set 154A
and need not be provided herein as such is not deemed
necessary. Instead, like numerals will indicate the
same component members of the second fork se-t 154B.
Accordingly, the second fork set 154B also comprises a
laterally extending beam member 156 and a plurality of
fork mernbers 156A that are extendible and retrac-table
relative to the frame 164 via a bearing block 156B
supported and positionable via appropriately disposed,
but not shown, screw members 156C. A cylinder 162 is
also provided, together with its rack gear 160C, suppor-
ted appropriately to actuate the components discussed
above with reference to Figure 12C for the movable
backstop 134, the result being the selective extension
and retraction of the second fork set 154B.
-~6-
The first and second Eork sets 154A and 154~ are
extendible toward each o-ther and intermesh somewhat to
form a temporary cradle beneath the vacuum conveyor
s~ation 18 to receive falling paperboard blanks to per-
mit removing of stacks of the blanks on the first eleva-
tor 118 without stopping the flow of such blanks. Fur-
ther, as the extended first and second fork sets 154A,
15~B collect Ealling blanks in the temporary cradle
provided thereby, the first and second fork sets 154A,
154B are progressively lowered via the supporting screw
members 156C. Once the first elevator 118 has been
lowered and cleared of i-ts stacks of blanks, the first
elevator 118 is again raised to just below-the forks of
the first and second fork sets 154A, 154B, and the forks
156A thereof are simul-taneously retracted in order to
transfer the collected blanks to the upper platform
surface of the first elevator 118.
A final detail of the movable backstop 134 will be
noted. The positioning of the movable backstop 134 is
determined along the supporting rails 164A to define the
length of the drop chute 90 to accommodate the size of
paperboard blanks being downstacked from the die cutter
assembly 24. Thus, the movable backstop 134 is posi-
tioned so as to serve as a back boundary at the rear
edges of the blanks carried over the drop chute 90 via
the vacuum conveyor station 18. Figure 13, again refer-
enced, shows the movable backstop 134.
168 depicts a panel member supported by -the frame
164 which serves as the back boundary of the falling
blanks in the drop chute 90. A portion of the panel
member 168 is shown in enlarged view in Figure 14 where
168A depicts an overhanging lip portion thereof. The
purpose of the lip portion 168A is to permit clearance
to the falliny blanks in the drop chute 90, but also, to
prevent upward flight of the rear edges of the blanks as
the blanks rebound from impac-t with the cushion wheels
140 of the stationary backstop 132. This feature has
proven helpful to prevent the trailing edges o~ the
blanks from going upward into the advancing path of
~3~Z~7
-27-
following blanks, and it is believed to be useful in the
avoidance of some po-tential jams.
It will be appreciated t'hat the above description
necessarily is brief and does not include many details
of cons-truction of the downstacker assembly 10. How-
ever, such details that have been provided will be
sufficient for the practice of the invention as the
details omitted are well within the knowledge of persons
of ordinary s~ill in the related field. ~urther, the
following discussion of a control system for the down-
stacker assembly 10 should prove helpful in an under-
standing of the operation thereof.
170 in t'he schematic diayram of Figure 1~ repre-
sents a control system which ties together the opera-
tions of the various stations and assures a continuousopera-tion of the progressive s-teps in the work performed
by the downstacker assembly 10. The control system 170
first con-trols the flow of paperboard blanks from the
die cutter assembly 24. The die cutter assembly 24 does
not form a part of the present invention, as the down-
stacker assembly 10 may find usefulness in other unit
operations involving blanks and the like. ~evertheless,
the control system 170 is tied in a control sense to the
die cutter assembly 2~ in order to command responses
from the several work stations of the do~nstacker assem-
bly 10 in a coordinated manner appropriate to the blanks
provided by the die cutter assembly 2~.
The above description makes clear that a number of
motor drive~ are used throughout the downstacker assem-
bly 10 to drive the blanks from input at the trimremoval station 12 to where the blanks are caused to
fall by the cooperative efforts of the strikers 92 and
the cushion wheels 140 into stacks formed beneath the
vacuum conveyor sta-tion 18~ A conventional manner of
counting and tracking the location of'blanks through
this journey, although travelling at high linear speeds,
is practiced, for example, by the use of shift register
and computer controls. The art of shift register con-
-28-
trol is well known, and information readily available,
such as Erorn the General Electric Company and other
manufacturers, is incorporated herein by reference.
Genera] Electric Series One Program}ning, GEK-25375, is
one such shift reyister and programtning guide which is
available.
In a shift register setup, a group of data collec-
tion and storage locations are synchronized by timing
signals genera-ted a-t motor locations at the various work
stations. This data is sent to, and accumulated by, the
shift register stations and the central control systern
170. Thus, the number of blanks and location of same
are tracked, beyinning with the die cutter asse~lbly 24,
as shown in E'igure 18, to include-the trim removal
station 12, the Eeed station 14, t'he downstacker station
16 (including the vacuum conveyor station 18), and t'he
stack retrieval assembly 120. '~'his permits the con-trol
systen~ 170 to be progra~ned to stop the die cutter
assembly 24, which stops the feed of paperboard blanks
to the trim rernoval station 12 for a predetermined time
interval -to create a gap between blanks flowing through
the downstacker assembly 10, the purpose of which will
now be discussed.
With reference to the discussion of the stack stag-
ing assembly found hereinabove, it will be rememberedthat -the fork members 156~ are caused to be positioned
beneath the vacuum conveyor station 18 to form a tempor-
ary cradle to catch t'he falling blanks during the time
interval of stack removal from the first elevator 118.
While it is possible to move the forks 156A into cradle
position during the time in which blanks are falling in
the drop chute 90, the probability o~ causing blank
interference by such fork insertion increases as the
rate of blank flow is increased. It has been determined
that blank jams of this type can be eliminated by pro-
viding a gap of abou-t a three second duration in the
flow of blanks. This is effected by the control syste
170 siynalling a time delay to the die cutter assembly
24, after ~hich time the die cutter assembly 24 again is
-29-
caused to feed blanks to the trim removal station 12.
This yap in the flow of paperboard blanks can be elec-
trically -tracked so -that -the arrival of the gap at the
drop chu~e 90 is known, and the forks 156A of the stack
staging assernbly can be extended across the drop chute
90 during the gap time without interference with the
falliny blanks.
Other features of the control system 170, such as
the operations of starting and stoppiny, jogging and
speed controlling of the downstacker assembly 10, will
be commonly known and need not be described herein. It
will be appreciated then that the control system 170
will be a useful feature of the downstacker assembly 10.
:tt is clear that the present invention is well
adapted to carry out the objects and to a-ttain -the ends
and advarltages mentioned herein as well as those inher-
ent in the invention. While a presently preferred
embodiment of the invention has been described for pur-
poses of this disclosure, numerous changes may be made
which will readily suggest themselves to those skilled
in the art and which are accomplished within the spirit
of the invention disclosed and as defined in the 25
appended claims.
